Three-dimensional (&#34;3d&#34;) printing apparatus with counter-rotating roller

ABSTRACT

A three-dimensional (“3D”) printing system for printing on a substrate, the printing system including a plurality of powder feeders, the plurality of powder feeders dispensing a powder on the substrate in a first direction and in a second direction; and a powder uniformization device located adjacent to the plurality of powder feeders, the powder uniformization device rotatable along the substrate in directions opposing the first direction and the second direction.

TECHNICAL FIELD

Various aspects of the current application relate to a three-dimensional(“3D”) printing apparatus with improved powder deposition of thinlayers. Specifically, various aspects relate to a 3D printing apparatushaving a counter-rotating roller and powder feeder configured as ablade, both the counter-rotating roller and the blade having anindependently adjustable height.

BACKGROUND

The introduction of three-dimensional (“3D”) printing has generated ahigh degree of interest in the potential for a faster and moreeconomical manufacturing approach. 3D printers may typically employpowder-bed technology, but with different approaches to fixing thepowder into the desired configuration. Also, jetted binder 3D printersmay benefit from the ability to rapidly deposit a full layer of powderand fix the desired pattern with a high-speed ink jet-like print head.The most significant limiting factor of a jetted binder-type 3D printeris the restriction to a single material within each layer.

Typical powder-bed 3D printing relies on the successive deposition ofvarious layers on top of one another, or the generation of a foundationon which to deposit layers on a layer-by-layer basis. Depositing thinlayers in the order of 25 μm to 200 μm on a substrate is typicallydifficult to achieve because of friction generated by the powders andlow flowability of the powders. In addition, compacting a deposited thinlayer is typically difficult to achieve. In some systems that deposit apowder or a slurry, in order to uniformize the deposited powder orslurry, existing systems typically rely on a blade to level the powderor slurry and to promote a uniform deposition in 3D printing systems.However, such blades, particularly flat blades, may impose sheer forcesto the deposited powder or slurry that may disturb uniformity of thedeposited powder or slurry and may thus prevent or hinder the formationof thin layers. Other systems rely on counter-rotating rollers topromote uniformity of the deposited powder. However, though they enablethe use of lower flowability powders, counter-rotating rollers maysuffer from the accumulation of powder in front of the roller, andnon-uniform compacting of the powder because of, i.e., the sheer forcesapplied to the powder by the roller. In addition, as the depositedpowder has a non-uniform thickness, the powder may accumulate in frontof the roller and have a decreasing thickness the further it is from theroller. Also, as powder accumulates in front of the roller, the powdermay be unable to rotate under the action of the roller and may insteadslide under the roller, which increases the compaction of the powder,creates a non-uniform deposition of the powder, and results in a poor 3Dprinted product.

SUMMARY

In one general aspect, the instant application describes athree-dimensional (“3D”) printing system for printing on a substrate,the printing system including a plurality of powder feeders, theplurality of powder feeders dispensing a powder on the substrate in afirst direction and in a second direction; and a powder uniformizationdevice located adjacent to the plurality of powder feeders, the powderuniformization device rotatable along the substrate in directionsopposing the first direction and the second direction.

The above general aspect may include one or more of the followingfeatures. For example, the first direction opposes the second direction.A lower surface of a blade-shaped end of each powder feeder is parallelto the substrate. Additionally, the powder uniformization device mayinclude a roller. The substrate may be movable with respect to theprinting system along a longitudinal axis, and the printing system maybe static with respect to the longitudinal axis. Alternatively, theprinting system may be movable with respect to the substrate along thelongitudinal axis, and the substrate may be static with respect to thelongitudinal axis. Alternatively, both the printing system and thesubstrate may be movable with respect to each other along thelongitudinal axis.

For another example, a distance between a lowest contact point of thepowder uniformization device to the substrate and each blade-shaped endis equal to about one radius of the powder uniformization device.Further, each powder feeder is located along a longitudinal axis of theprinting system. Additionally or alternatively, each powder feeder islocated along a longitudinal axis of the substrate. In embodiments, eachpowder feeder is synchronized depending on which direction the powderfeeders are moving relative to the substrate. Alternatively oradditionally, each powder feeder is synchronized depending on whichdirection the substrate is moving relative to the powder feeders.

The printing system may further include a vibrating device configured tovibrate the powder uniformization device at a specific frequency.Alternatively, the print station may further include a vibrating deviceconfigured to vibrate the substrate. In embodiments, the powderuniformization device rotates in one direction for a first powder feederand an opposite direction for a second powder feeder. Additionally oralternatively, each powder feeder includes at least one of adehumidifier, a heating element, and an inert gas enclosed therein. Theprinting system may further include a cleaning device configured toremove residual powder from the powder uniformization device. Thecleaning device may be configured to apply an electric charge to thepowder uniformization device. The printing system further includes atleast one of a fixing device and a binder printer. The activation of thepowder feeders may be synchronized with a direction of travel of one ormore of the powder feeders and the substrate. The plurality of powderfeeders is configured to dispense more than one material.

In another general aspect, the instant application describes a methodfor three-dimensional (“3D”) printing using a printing system, themethod including arranging the printing system over a substrate.Additionally, the method includes distributing a first powder on thesubstrate in a first direction using a first powder feeder of theprinting system, and uniformizing the first powder by a uniformizationdevice located at a first distance from the first powder feeder.Further, the method includes distributing a second powder on thesubstrate in a second direction using a second powder feeder of theprinting system, and uniformizing the second powder by theuniformization device located at a second distance from the secondpowder feeder.

In another aspect, the uniformization device rotates in a firstdirection to uniformize the first powder and a second direction touniformize the second powder, wherein the first and second directions ofthe uniformizing device rotation oppose the first and second directionsof powder distribution, respectively.

In a further aspect, the method includes synchronizing a direction ofthe uniformization device based on a direction the substrate is movingrelative to the first and second powder feeders. Alternatively, themethod includes synchronizing a direction of the uniformization devicebased on directions of the first and second powder feeders are movingrelative to the substrate.

These general and specific aspects may be implemented using a system, amethod, or a computer program, or any combination of systems, methods,and computer programs.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

Additional advantages and novel features of these variousimplementations will be set forth in part in the description thatfollows, and in part will become more apparent to those skilled in theart upon examination of the following or upon learning by practice ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accord withthe present teachings, by way of example only, not by way of limitation.In the figures, like reference numerals refer to the same or similarelements. Furthermore, it should be understood that the drawings are notnecessarily to scale.

FIG. 1 illustrates a schematic representation of a typical 3D printingapparatus including a print station and a continuous substrate.

FIG. 2 illustrates a schematic representation of a print station inaccordance with various example implementations.

FIG. 3A illustrates a portion of a print station including a powderfeeder and a counter-rotating roller, in accordance with various exampleimplementations.

FIG. 3B illustrates a detailed portion of the print station illustratedin FIG. 3A, in accordance with various example implementations.

FIG. 3C illustrates a blade, in accordance with various exampleimplementations.

FIG. 3D illustrates a schematic representation of a print station inaccordance with various example implementations.

FIGS. 4A-4B illustrate schematic representations of a print station inaccordance with various example implementations.

FIG. 5 illustrates a method of operation of a 3D print station inaccordance with various example implementations.

FIG. 6 illustrates a schematic representation of a print system inaccordance with various example implementations.

FIG. 7 illustrates a schematic representation of a print system inaccordance with various example implementations.

FIG. 8 illustrates a schematic representation of a print system inaccordance with various example implementations.

FIG. 9 illustrates a method of operation of a 3D print station inaccordance with various example implementations.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. It will be apparent to persons of ordinaryskill, upon reading this description, that various aspects can bepracticed without such details. In other instances, well known methods,procedures, components, and/or circuitry have been described at arelatively high-level, without detail, in order to avoid unnecessarilyobscuring aspects of the present teachings.

Current 3D printing systems present a technical problem because bladesused to render the deposited powder uniform over a substrate maygenerate sheer forces that may prevent or hinder the printing of thinlayers of powder, e.g., in the range of 100 μm. Furthermore, rollersused to compact the deposited powders also introduce sheer forces thatmay prevent or hinder the uniform printing of thin layers of powder.This problem also applies to powder deposited in a powder bed.Accordingly, in the following description, the term “substrate” mayinclude a layer being provided by a powder bed.

To address these technical problems and more, in an example, thisdescription provides a technical solution allowing for uniform powderdeposition by using a powder feeder configured as an adjustable blade inconjunction with a counter-rotating roller positioned at a desireddistance from the powder feeder. To further address the above technicalproblems, in another example, this description provides anothertechnical solution independently adjusting the gap between the powderfeeder and the surface of the substrate, and the gap between thecounter-rotating roller and the surface of the substrate.

Various implementations include a print station of a three-dimensional(“3D”) printing apparatus, and method of 3D printing, the print stationincluding a substrate configured to hold a printed object, the substratehaving a longitudinal axis, and a print system over the substrate, theprint system including a powder feeder device having a blade-shaped end,and a powder uniformization device located at a distance from the powderfeeder device along a direction parallel to the longitudinal axis.

Various implementations include a powder deposition arrangementconfigured to facilitate uniform powder deposition of thin layers, wherethe powder is fed by a powder feeder that includes an adjustable blade,and the powder deposition arrangement also includes a counter-rotatingroller located at a given distance from the powder feeder and used tocompact the powder material during the process of 3D printing. Inaddition, the gap between the powder feeder and the substrate (feedergap) may be adjustable to increase the quality of the powder deposition.The gap between the powder feeder and the surface of the substratedefines the quality of the deposition by, e.g., minimizing thecompaction of the powder. As another example, the gap between thecounter-rotating roller and the substrate (roller gap) is alsoadjustable to a desired value in order to control the printed thicknessas well as quality of the thin layer deposition during the process of 3Dprinting, the roller gap being independently adjustable from the feedergap. For example, the roller gap may define the final thickness of theprinted layer, while, as discussed above, the powder feeder gap maydefine the quality of the deposition.

FIG. 1 schematically depicts a print station 100 and an assemblyapparatus 81 with a continuous substrate. In embodiments, a printstation 100 includes a printing system 1 and a substrate 10. As will bediscussed below, the printing system 1 includes a dispensing device 20,a compaction device 30, a binder printing device 40, a fixing device 50and a fluidized materials removal device 60. As shown in FIG. 1 , theprint station 100 can include a carrier device 12. In someimplementations, the carrier device 12 can include a conveyor configuredto transport or move materials from a first position to a secondposition. The conveyor can include a belt and two rotating elements 15,configured to rotate in the same direction to advance the belt in acertain direction. The carrier device 12 can have a distal end and aproximal end. The carrier device 12 can transport a substrate 10 fromthe distal end to the proximal end. The substrate 10 can be positionedby the two rotating elements 15 to a location where a transfer device 76can transport a printed layer (not shown) to a build substrate 80 in theassembly apparatus 81.

At the distal end of the carrier device 12, a dispensing device 20 canbe provided. The dispensing device 20 can simply be a dispenserconfigured to dispense fluidized material, e.g., a flowable powder. Thedispensing device 20 can include a materials storage 21 and a dispensingcontroller 22. The dispensing controller 22 can be configured to meteran amount of fluidized material deposited onto the substrate 10. Thedispensing controller 22 can also be configured to precisely control theuniformity of the deposited fluidized material.

Near the distal end of the carrier device 12, a compaction device 30 canbe provided. In some implementations, the compaction device 30 caninclude a roller, made up of a hardened metal material designed as acylindrical tube. In some implementations, the compaction device 30 canbe configured to compact a fluidized material to a high density of atleast 40% of the theoretical density of the fluidized material. Thecompaction device 30 rotates in the direction opposing the direction ofpowder distribution from right to left, i.e., in a counter-clockwisedirection opposing the spreading direction of the deposited powder layerwhen the substrate 10 moves from right to left while the dispensingdevice 20 and the compaction device 30 are static or not movable, asillustrated in FIG. 1 .

Near the distal end of the carrier device 12, a binder printing device40 can be provided. The binder printing device 40 can be configured todeposit a liquid binding material to fix a precise pattern into thefluidized material. The precise pattern can be fixed into the fluidizedmaterial by binding the fluidized material into a connected and robustmass. In some implementations, the binder printing device 40 can be anink jet type print head under direct control of a computer (not shown).

Near the center of the carrier device 12, a fixing device 50 can beprovided. The fixing device 50 can be configured to solidify the liquidbinding material, thus fixing the fluidized material exposed to theliquid binding material in a robust solid pattern. The fixing device 50can be a source of radiant energy that may interact with the liquidbinding material to cause it to become solid. In some implementations,the radiant energy can be IR radiation, UV radiation, electron beam, orother known radiation types. It should be understood the fixing device50 does not need to be limited to the disclosed radiation types, as thislist is presented for exemplary implementations and not intended to beexhaustive. Alternatively, the fixing device 50 can include a device fordispersing a reactive agent configured to react with the liquid bindingmaterial and the fluidized material to convert the fluidized material toa robust mass.

A fluidized materials removal device 60 can be provided downstream fromthe fixing device 50. The fluidized materials removal device 60 can beconfigured to remove all of the fluidized material deposited andcompacted onto the substrate 10. The fluidized materials removal device60 can remove the fluidized material deposited and compacted onto thesubstrate, but not fixed in place by the liquid binder material.

A transfer device 76 can be implemented downstream from the fluidizedmaterials removal device 60 in the assembly apparatus 81. The transferdevice 76 can be configured to move a printed layer (not shown) from thesubstrate 10. The printed layer can be moved from the substrate 10 to abuild substrate 80, or to the top of a stack of previously positionedlayers 91. The transfer device 76 can also include a pick-up assembly.The pick-up assembly can include an attachment device 71 configured toremove a printed layer from the substrate 10. The attachment device 71can include a vacuum device or an adhesive device to overcome the forceholding the printed layer to the substrate 10. The transfer device 76may also include a translation device 75 configured to move the printedlayer from the substrate 10 to the assembly apparatus 81.

The elevator device 90 is configured to maintain the level of the top ofthe stack of previously positioned layers 91. In an implementation, theelevator device 90 can include a linear motor device.

FIG. 2 illustrates a schematic representation of a print station with acontinuous substrate for depositing thin layers of powder on asubstrate, in accordance with various example implementations. Withreference to FIG. 1 , the printing system 210 may correspond to, e.g.,the combination of the dispensing device 20 and the compaction device30. In FIG. 2 , the print station 200 includes a support 220corresponding to the carrier device 12 and a printing system 210. Theprinting system 210 may be movable while the support 220 may be fixed,or the printing system 210 may be fixed while the support 220 ismovable. The printing system 210 may include a top support 230, anadjustable roller 240 configured to decrease or minimize non-uniformdeposition, and a powder feeder 250. The printing system 210 may alsoinclude a roller cleaner 260 to clean the roller 240 of any residualpowder that may remain thereon and that may contaminate the roller 240.

In operation, the powder is provided by the powder feeder 250 while theprinting system 210 is moving from right to left relatively to thesupport 220 which remains stationary, or the support 220 is moving fromleft to right relatively to the printing system 210 which remainsstationary. Accordingly, when the powder is provided by the powderfeeder 250, the powder is subsequently submitted to the rotating actionof the roller 240. For example, the roller 240 is a counter-rotatingroller, i.e., the roller 240 rotates in a direction 245 that is oppositeto a direction of the movement of powder feeder 250 or the direction ofthe spreading of the deposited powder layer. The roller 240 agitates thepowder after the powder is deposited on the substrate 270. Accordingly,the powder that is provided by the powder feeder 250 is uniformized bythe action of the roller 240.

The roller 240 also applies a pressure to the powder after the powder isdeposited on the substrate 270. Accordingly, the powder that is providedby the powder feeder 250 is uniformized by the action of the roller 240.The roller 240 may be installed with an adjustable angle so that theaccumulated powder may be released behind the roller.

FIG. 3A illustrates a portion of a print system 300 including a powderfeeder 350 and a counter-rotating roller 340, in accordance with variousexample implementations. With reference to FIG. 1 , the print system 300may correspond to, e.g., the combination of the dispensing device 20 andthe compaction device 30. Further, a print station may include the printsystem 300 and the substrate 370. In various implementations, the printsystem 300 includes a powder feeder 350, and the powder feeder 350 has ablade 375 integrated or included therein, so that when the powder exitsthe powder feeder 350 at the blade 375 located at the exit point of thepowder feeder 350, the powder is flattened and at least partiallyuniformized by the blade 375. FIG. 3C provides an illustration of theblade 375. For example, the blade 375 ensures that the thickness of thepowder that is deposited by the powder feeder 350 remains substantiallythe same. In addition, for example, a counter-rotating roller 340 ispositioned at a given distance from the blade 375, the counter-rotatingroller 340 further planarizing and uniformizing the powder that exitsthe powder feeder 350 at the blade 375. For example, thecounter-rotating roller 340 may enable a uniform deposition of lessflowable powders. The blade 375 may ensure that the thickness of thepowder that is deposited by the powder feeder 350 remains substantiallythe same as it approaches the counter-rotating roller 340. As a result,powder accumulation in front of the counter-rotating roller 340 may beavoided or reduced.

The powder feeder 350 may also ensure the ability to maintain and/orreduce the sheer forces applied to the printed powder during powderdeposition, and may thus allow the printing of thin layers, e.g., in therange of 100 μm, on a substrate 370. The powder feeder 350, whichincludes the blade 375, may have an adjustment arrangement configured toadjust the gap between the powder feeder 350/blade 375 and a surface ofthe substrate 370. The counter-rotating roller 340 may alsoindependently have an adjustment arrangement configured to adjust thegap between the counter-rotating roller 340 and the surface of thesubstrate 370.

In various implementations, the print system 300 may further include aroller cleaner 380 configured to clean the counter-rotating roller 340.For example, the roller cleaner 380 can remove unwanted powder particlesthat may remain on the counter-rotating roller 340 after thecounter-rotating roller 340 distributed the powder. In addition, as theprint system 300 may be movable with respect to the underlying substratesuch as, e.g., substrate 10 illustrated in FIG. 1 , the blade 375 isalso movable with respect to the substrate. In other examples, thesubstrate is movable with respect to the print system 300, and thusmovable with respect to the blade 375.

In various implementations, the counter-rotating roller 340 rotates at aspeed in the range of 10 RPM to 300 RPM. If the counter-rotating roller340 has a rotating speed that is greater or lower than this range, thenthe resulting quality of the powder deposition may be deterioratedbecause the uniformity of the deposited powder may be affected by thecounter-rotating roller.

In various implementations, a lubricant agent and/or a wetting agent isadded to the powder being distributed by the powder feeder 350 in orderto, e.g., increase the flowability of the powder that is deposited infront of the counter-rotating roller 340. Adding such lubricant agentand/or a wetting agent may improve the compaction of the powder andminimize or control the tension between the substrate and the compactedpowder layer. Specifically, the lubricating agent facilitates obtaininga uniform compaction of the powder that is compacted by thecounter-rotating roller 340. In implementations, the print system 300may include a single counter-rotating roller 340, and may avoid havingto have an additional compacting roller that rotates in the samedirection of the spreading of the deposited powder, i.e., rotates in theopposite direction to the rotation direction of a counter-rotatingroller 340. Example lubricating agents and wetting agents include waterand isopropyl alcohol.

FIG. 3B illustrates a detailed portion of the print station illustratedin FIG. 3A, in accordance with various example implementations. Invarious implementations, the portion referred to as “A” in FIG. 3A isdiscussed in greater detail below. In FIG. 3B, the counter-rotatingroller 340 has a radius R, and a distance “d” between a lowest contactpoint of the counter-rotating roller 340 to the substrate 370, with thelowest contact point being labeled as “B,” and the end point of theblade, labeled as 375 a. This distance “d” may be in a range of one totwo R, for example. 1.5R. In a particular example, the distance “d” maybe equal to about R. If the distance “d” is much greater than R, thenthe powder may undergo rotation in front of the counter-rotating roller340, which results in a poor powder deposition such as, e.g.,non-uniform deposition.

In various implementations, a feeder gap 390 between the lowest portionof the powder feeder 350 and the surface of the substrate 370 may beadjustable as desired. Accordingly, the feeder gap 390 between thesubstrate and the powder feeder 350, or between the previously depositedpowder layer and the powder feeder 350 may be maintained at a desiredconstant, or substantially constant value to ensure uniform thickness ofthe deposited powder layer. For example, in order to deposit a singlelayer of powder, the feeder gap 390 between the substrate 370 and thepowder feeder 350 may be adjusted accordingly. The feeder gap 390between the surface of the substrate 370 and the lowest portion of thepowder feeder 350 defines the quality of the deposition. In otherimplementations, the feeder gap 390 may be defined between the lowestportion of the blade 375 and the surface of the substrate 370, or thesurface of a previously deposited powder layer.

In some implementations, the counter-rotating roller 340 may also havean adjustable roller gap 395 between the lowermost surface thereof andthe substrate 370. In embodiments, the roller gap 395 beingindependently adjustable from the feeder gap 390. In addition, theroller gap 395 defines a final thickness of the printed layer, while, asdiscussed above, the feeder gap 390 defines the quality of thedeposition. In embodiments, the feeder gap 390 may be greater than theroller gap 395. For example, the feeder gap 390 is greater than theroller gap 395 and equal to or lower than one-half of the diameter ofthe counter-rotating roller 340. If the feeder gap 390 is greater thanone-half of the diameter of the counter-rotating roller 340, then thepowder may undergo rotation in front of the counter-rotating roller 340,which results in a poor powder deposition such as, e.g., non-uniformdeposition.

In some implementations, as illustrated by FIG. 3D, the print system 300includes the counter-rotating roller 340, the powder feeder 350 withblade 375, one or more sensors 325, 330, 335, and a control apparatus360. The one or more sensors 325, 330, 335 may comprise point,multi-point or continuous level devices for sensing one or moreparameters of a thickness of a powder level, a powder level, or asurface profile or topography of the powder deposited by the powderfeeder 350, amongst other parameters. As an example, the one or moresensors 325, 330, 335 include an ultrasonic thickness sensor, or anoptical sensor (such as a laser sensor), though a person of skill in theart will recognize that other forms of thickness or topographic sensorscan alternatively be used to measure parameters with respect to thepowder deposited by the powder feeder 350. In a particular example,sensors 325 and 330 are located upstream from the counter-rotatingroller 340, and sensor 335 is located downstream from thecounter-rotating roller 340. The one or more sensors 325, 330, 335 areconnected to the control apparatus 360.

For the purposes of explanation, FIG. 3D also indicates illustrativethickness levels of the powder deposited by the powder feeder 350 atvarious stages throughout operation of the print system 300 in a 3Dprinting apparatus, in accordance with an example implementation. Withreference to FIG. 3D, the dashed line 315 represents a level of powderafter it has been deposited by the powder feeder 350, prior toencountering the blade 375. The dashed line 310 represents a powdersurface level or thickness 310 after the powder has been at leastpartially uniformized by the blade 375, prior to encountering thecounter-rotating roller 340. Powder surface level 320 is a surface levelor thickness of the powder after the powder has been further planarizedand uniformized by the counter-rotating roller 340, shown as a dashedline 320.

In order for an optimum operation of the counter-rotating roller 340,and to reduce an accumulation of powder in front of the counter-rotatingroller 340 and achieve uniform compacting of the powder, in oneimplementation, sensor 325 may be utilized to acquire a first powdersurface height measurement of the powder surface level 310, at one ormore locations between the blade-shaped end of the powder feeder 350 andthe counter-rotating roller 340, for example, just before thecounter-rotating roller 340. The measurement data acquired from sensor325 may be conveyed to the control apparatus 360, in which a processingunit (not shown) compares the acquired data of the powder surface level310 to a first predetermined powder surface height threshold valuestored in a memory of the control apparatus 360. The first predeterminedpowder surface height threshold value is a maximum height at which thepowder deposited by the powder feeder 350 should be allowed toaccumulate. Above the first predetermined powder surface heightthreshold value, powder accumulation in front of the counter-rotatingroller 340 would create conditions resulting in the powder not beingable to rotate under the counter-rotating roller 340, and increasing thepotential of a non-uniform powder layer being created.

Should the processing unit determine that the first powder surfaceheight measurement of the powder surface level 310 is above the firstpredetermined powder surface height threshold value, the controlapparatus 360, via a control unit for the blade 375, adjusts the heightof the blade 375 above the substrate 370, reducing it such that lesspowder is allowed to approach the counter-rotating roller 340. Theamount of adjustment may be determined by the processing unit based on adata table or similar predetermined data, amongst other examples. Insome implementations, adjusting the height of the blade 375 above thesubstrate 370 may comprise lowering the blade 375 such thatsubstantially no further powder is allowed to approach thecounter-rotating roller 340.

In some implementations, alternatively, or additionally, an amount ofpowder distributed by the powder feeder 350 may be adjusted. In oneexample, sensor 330 may be utilized to acquire a second powder surfaceheight measurement of the powder surface level 315, at one or morelocations before the powder encounters the blade 375. The measurementdata acquired from sensor 330 may be conveyed to control apparatus 360,in which a processing unit (not shown) compares the acquired data to asecond predetermined powder surface height threshold value stored in amemory of the control apparatus 360. The second predetermined powdersurface height threshold value is a maximum height at which the powdershould be allowed to accumulate before the blade 375.

Should the processing unit determine that the second powder surfaceheight measurement of the powder surface level 315 is above the secondpredetermined powder surface height threshold value, the controlapparatus 360, via a control unit (not shown) for the powder feeder 350,adjusts the amount of powder dispensed, reducing it such that lesspowder is dispensed before approaching the blade 375. In one example,the control unit may communicate with the dispensing controller 22 (seeFIG. 1 ) to adjust the amount of fluidized material metered. The amountof adjustment may be determined by the processing unit based on a datatable or similar predetermined data, amongst other examples. In someimplementations, adjusting the powder dispensed by the powder feeder 350may include closing an output of the powder feeder 350 such thatsubstantially no further powder is dispensed.

In other implementations, alternatively, or additionally, sensor 335 maybe utilized to acquire a third powder surface height measurement of thepowder surface level 320, at one or more locations after passing underthe counter-rotating roller 340, or downstream from the counter-rotatingroller 340. The measurement data acquired from sensor 335 may beconveyed to control apparatus 360, in which a processing unit (notshown) compares the acquired data to a desired powder surface heightvalue, or desired range of values, stored in a memory of the controlapparatus 360. Should the processing unit determine that the thirdpowder surface height measurement of the powder surface level 320deviate from a desired value or range of values of the desired powdersurface level, the control apparatus 360, via a control unit (not shown)for the counter-rotating roller 340, adjusts the height of the lowestcontact point of the counter-rotating roller 340 to the substrate 370.The amount of adjustment may be determined by the processing unit basedon a data table or similar predetermined data, amongst other examples.In some implementations, in addition or alternatively to adjusting theheight of the lowest contact point of the counter-rotating roller 340 tothe substrate 370, the amount of powder that passes under the blade 375may also be adjusted.

In some implementations, one or more of the sensors 325, 330, 335continually monitor powder thickness, powder level or topographical datain real-time, and adjust the one or more of the heights of thecounter-rotating roller 340 and/or the height of the blade 375 above thesubstrate, and/or the amount of powder dispensed by the powder feeder350. In other implementations, the control apparatus 360 may beconfigured to enable one or more feedback operations between one or moreof the sensors 325, 330, 335, and control units associated with thepowder feeder 350, blade 375 and counter-rotating roller 340. In thismanner, the feedback, in association with control algorithms can beutilized to provide dynamic adjustment to maintain consistency in thepowder uniformization process of a 3D printing operation.

The control apparatus 360 may comprise software architecture, variousportions of which may be used in conjunction with various hardwareelements described herein. It will be appreciated that the softwarearchitecture may be implemented to facilitate the functionalitydescribed herein. The software architecture may be executed on hardwaresuch as a central processing unit that may include, among other things,document storage, processors, memory/storage, and input/output (I/O)components. The architecture may include a processing unit andassociated executable instructions. The executable instructions mayinclude implementation of the methods, modules and so forth describedherein. The architecture may also include other hardware modules.Drivers may be responsible for controlling or interfacing with theunderlying hardware. Drivers may include display drivers, cameradrivers, memory/storage drivers, peripheral device drivers, networkand/or wireless communication drivers, audio drivers, and so forthdepending on the hardware and/or software configuration. Libraries,including data libraries may provide a common infrastructure that may beused by applications and/or other components.

In various implementations, the counter-rotating roller 340 may becoated by a coating (not shown). For example, the coating may be ananodized coating, a Teflon coating, or a plastic coating. A plasticcoating may minimize the friction between the powder and thecounter-rotating roller 340, and may also minimize powder sticking oradhering on the counter-rotating roller 340. For example, duringoperation of the print system 300, the powder that is distributed by thepowder feeder 350 and compacted by the counter-rotating roller 340 mayadhere to the surface of the counter-rotating roller 340. The powderadhered on the counter-rotating roller 340 may impact the quality ofsubsequent layers of the 3D printed product. A plastic coating on thecounter-rotating roller 340 may decrease such powder sticking.Similarly, an anodized coating to the counter-rotating roller 340 mayprovide a decreased powder sticking, and may also reduce frictionbetween the surface of the counter-rotating roller 340 and the substrate370. As an example, the coating may reduce electrostatic charging of thepowder during operation of the print system 300. As another example, athickness of the coating is in a range of 0.1 nm to 500 μm.

FIGS. 4A-4B illustrate schematic representations of a print station inaccordance with various example implementations. In FIG. 4A, the printstation 400 a includes roller 440, powder feeder 450 comprising blade475, and substrate 470. With reference to FIG. 3A, roller 440 maycorrespond to roller 340, and powder feeder 450/blade 475 may correspondto powder feeder 350/blade 375, and substrate 470 may correspond tosubstrate 370. In FIG. 4A, the print station 400 a further includes avibrating device 410 a. For example, the vibrating device 410 a isfunctionally connected, e.g., integrally connected, to the roller 440,and may be configured to vibrate at a rapid frequency in order to makethe roller 440 vibrate at the rapid frequency. For example, thevibrating device 410 a may vibrate at, e.g., an ultrasonic frequency andthus makes the roller 440 vibrate at the ultrasonic frequency. As aresult of the roller 440 vibrating at a rapid frequency, e.g., at anultrasonic frequency, the powder that is in contact with the roller 440during the counter-rotation of the roller 440 may be better distributed,and agglomeration of the powder at the point of contact with the roller440, or in the vicinity of the point of contact with the roller 440, maybe reduced, significantly reduced, or eliminated.

In FIG. 4B, the print station 400 b includes roller 440, powder feeder450 that includes blade 475, and substrate 470. With reference to FIG.3A, roller 440 may correspond to roller 340, powder feeder 450 maycorrespond to powder feeder 350, and blade 475 may correspond to blade375, and substrate 470 may correspond to substrate 370. In FIG. 4B, theprint station 400 b further includes a vibrating device 410 b. Forexample, the vibrating device 410 b is functionally connected, e.g.,integrally connected, to the substrate 470, and may be configured tovibrate at a rapid frequency in order to make the substrate 470 vibrateat the rapid frequency. For example, the vibrating device 410 b mayvibrate at, e.g., an ultrasonic frequency and thus makes the substrate470 vibrate at the ultrasonic frequency. As a result of the substrate470 vibrating at a rapid frequency, e.g., at an ultrasonic frequency,the powder that is deposited by the powder feeder 450 on the substrate470 may be better distributed on the substrate 470, and agglomeration ofthe powder at the point of contact with the roller 440, or in thevicinity of the point of contact with the roller 440, may be reduced,significantly reduced, or eliminated. In various implementations, theprint station 400 a/400 b may include both vibrating devices 410 a and410 b, in which case both the roller 440 and the substrate 470 are madeto vibrate at the rapid frequency during deposition and distribution ofthe powder.

In various implementations, the powder feeder 450 may enclose thereinone or more devices or elements 460 designed to control or influence theenvironment where the powder is stored before being distributed. Forexample, the devices or elements 460 may be any combination of adehumidifier, one or more heating elements, and an inert gas providerconfigured to provide an inert gas inside the powder feeder 450. Any oneof these devices or elements 460, whether alone or in combination, maybe enclosed in the powder feeder 450 in order to ensure that the powderremains sufficiently dry and un-agglomerated, and thus to ensure asufficient quality of the resulting printed layer.

In various implementations, the counter-rotating roller 440 may includean electric charging mechanism 420 that delivers an electric charge tothe surface of the counter-rotating roller 440 to remove any powder thatmay adhere to the surface of the counter-rotating roller 440 via staticcharging. Alternatively, the electric charge delivered to the surface ofthe counter-rotating roller 440 by the electric charging mechanism 420may prevent the powder from adhering to the surface of thecounter-rotating roller 440 via static charging.

FIG. 5 illustrates a method of operation of a print station in a 3Dprinting apparatus, in accordance with various example implementations.In the process 500 of FIG. 5 , at S510, a print system is arranged overa substrate, the substrate having a longitudinal axis. With reference toFIG. 2 , the printing system 210 is arranged over the substrate 270 orthe support 220. The process 500 continues to S520, where a powder isdistributed on the substrate through a powder feeding device of theprint system. For example, the powder is distributed on the powder bedof a print station that is part of a 3D printing apparatus. Withreference to FIGS. 3A and 3B, the powder is distributed from the powderfeeder 350. In implementations, a lubricating agent and/or a wettingagent may be added to the powder that is distributed at S520, thelubricating agent and/or wetting agent being configured to increase theflowability of the powder and the compaction uniformity. By controllingthe surface tension of the powder, the lubricating agent and/or wettingagent may also prevent or reduce powder sticking to the roller.

In various implementations, as the powder is distributed at S520, theprocess 500 continues to S530 by contemporaneously or simultaneouslyflattening the distributed powder via, e.g., a blade integrated into thepowder feeding device. For example, the flattening at S530 may maintaina constant thickness of the powder distributed on the substrate. Withreference to FIGS. 3A and 3B, as the powder is distributed via thepowder feeder 350, the powder is contemporaneously flattened by theblade 375. The process 500 continues to S540 where the powder istransported to a uniformization device along a moving direction of thepowder, the moving direction being parallel to the longitudinal axis ofthe substrate. For example, the uniformization device may be a rollerlocated at a desired distance from the blade 375, the roller beingconfigured to apply a pressure on the powder. The process 500 continuesto S550 where the powder is uniformized by the uniformization device.With reference to FIGS. 3A and 3B, the powder is uniformized by thecounter-rotating roller 340 which rotates and applies pressure on thepowder. In implementations, the counter-rotating roller 340 rotates in adirection opposing the moving direction of the powder or the directionof the spreading of the deposited powder on the substrate. The process500 continues to S560, where the powder is transferred to the nextstation in the 3D printing process such as, e.g., binder printing in aprinting device, fixing in a fixing device, or transferred to a transferdevice. With reference to FIG. 1 , the powder may be transferred to thebinder printing device 40, the fixing device 50, or the transfer device76.

FIG. 6 illustrates a schematic representation of print system 600, inaccordance with various example implementations described with respectto FIGS. 1-5 . With reference to FIGS. 1-5 , print system 600 includes aplurality of powder feeders 650, 655. The powder feeders 650, 655, maydispense the same powder as each other, or different powders, allowingfor multi-material deposition. Further, FIG. 6 illustrates each powderfeeder of the powder feeders 650, 655 is attached to a support ormounting apparatus 610. In some embodiments, each powder feeder of thepowder feeders 650, 655, is located along a longitudinal axis of theprint system 600, a longitudinal axis of the support or mountingapparatus 610, and/or a longitudinal axis of the substrate 670. Theprint system 600 may include one or more powder uniformization devices640, which may be attached to the same support or mounting apparatus 610to move together with the powder feeders 650 and 655. Alternatively, thepowder uniformization device 640 may be attached to a support ormounting apparatus different from support or mounting apparatus 610 tomove independently with the powder feeders 650, 655. In someembodiments, support or mounting apparatus 610 is configured to controlmovement of the powder feeders 650, 655 and powder uniformization device640, via a controller (not shown), either from right to left, or fromleft to right along the longitudinal axis formed by the support ormounting apparatus 610, in order to deposit powder on the substrate 670.Alternatively, or additionally, the support or mounting apparatus 610 isconfigured to control the movement of the powder feeders 650, 655 andpowder uniformization device 640 in a direction, substantiallyperpendicular to the longitudinal axis form by the support or mountingapparatus 610 in order to deposit powder on the substrate 670. In someembodiments, one of the support or mounting apparatus 610 and thesubstrate 670 is configured to move in first and second directions,wherein the first direction may be opposed to the second direction,substantially parallel to the longitudinal direction, while the other ofthe support or mounting apparatus 610 and the substrate 670 remainsstationary. In some implementations, the support or mounting apparatus610, the powder feeders 650, 655, and the powder uniformization device640 are movable together. Alternatively, the support or mountingapparatus 610 is static while the powder feeders 650, 655 and the powderuniformization device 640 are movable. In some embodiments, the printsystem 600 may be movable with respect to the substrate 670 along thelongitudinal axis formed by the substrate 670, and the substrate 670 mayremain stationary with respect to the longitudinal axis. In otherembodiments, the substrate 670 may be movable with respect to the printsystem 600 along the longitudinal axis formed by the substrate 670, andthe print system 600 may remain stationary with respect to thelongitudinal axis. Alternatively, both the print system 600 and thesubstrate 670 may be movable with respect to each other along thelongitudinal axis.

In some embodiments, the print system 600 may further comprise a carrierdevice, as illustrated in FIG. 1 (which may include a conveyor) totransport the substrate 670 from a first location to a second location.

In some embodiments, the powder feeders 650, 655, may correspond topowder feeders 350, 450, and may include all of their features asdescribed with respect to FIGS. 3A, 3B, 4A, and 4B, including eachpowder feeder of the powder feeders 650, 655, having a blade-shaped end.In some embodiments, each blade-shaped end has a lower surfacesubstantially parallel to the substrate 670. In further embodiments, adistance between a lowest contact point of the powder uniformizationdevice 640 to the substrate 670 and an end point of each blade of eachpowder feeder of the powder feeders 650, 655, is equal to about oneradius of the roller of the powder uniformization device 640. As afurther example, the powder feeders 650, 655, may each enclose one ormore devices or elements designed to control or influence theenvironment where the powder is stored before being distributed by anyone of the powder feeders 650, 655. As a further example, the devices orelements may be any combination of a dehumidifier, one or more heatingelements, and an inert gas provider configured to provide an inert gasinside the powder feeders 650, 655. Any one of these devices or elementsmay be enclosed in any one of the powder feeders 650, 655, in order toensure that the powder remains sufficiently dry and un-agglomerated, andthus to ensure a sufficient quality of the resulting printed layer.

As shown in FIG. 6 , the print system 600 includes a uniformizationdevice, i.e., powder uniformization device 640, located adjacent atleast one powder feeder of the plurality of powder feeders 650, 655. Forexample between the plurality of powder feeders 650, 655. The powderuniformization device 640 uniformizes powder deposited by the powderfeeders 650, 655 onto the substrate 670. In some embodiments, the powderuniformization device 640 may include a roller which corresponds torollers 340, 440, and may include all of their features as describedwith respect to FIGS. 3A, 3B, 4A, and 4B.

In some embodiments, the powder feeders 650, 655 may contain differentpowder materials, and the powder uniformization device 640 may comprisetwo or more powder uniformization devices (not shown). Theimplementation of two or more powder uniformization devices ensures thatthere is no powder cross contamination. For example, in the case wherepowder feeder 650 dispenses a first powder material, and powder feeder655 dispenses a second powder material, powder uniformization device 640may comprise two independent powder uniformization devices 640 a and 640b (not shown). With powder uniformization device 640 a operated touniformize powder deposited by the powder feeder 650, and powderuniformization device 640 b operated to uniformize powder deposited bythe powder feeder 655.

In further embodiments, the print system 600 may include a vibratingdevice (not shown) connected to a roller of the powder uniformizationdevice 640, similar to vibrating device 410 a functionally connected tothe roller 440. Further, the print system 600 may include a vibratingdevice (not shown) connected to the substrate 670, similar to thevibrating device 410 b functionally connected to the substrate 470. Inembodiments, these vibrating devices of the print system 600 areconfigured to vibrate at a rapid frequency in order to make the rollerof the powder uniformization device 640 or the substrate 670 vibrate atthe rapid frequency, similar to vibrating devices 410 a, 410 breferenced in FIGS. 4A and 4B. For example, a vibrating device of theprint system 600 may vibrate at, e.g., an ultrasonic frequency, therebymaking the roller of the powder uniformization device 640 vibrate at theultrasonic frequency. As a result of the roller of the powderuniformization device 640 or substrate 670 vibrating at a rapidfrequency, e.g., at an ultrasonic frequency, the powder that is incontact with the roller of the powder uniformization device 640 may bebetter distributed. Further, an agglomeration of the powder at the pointof contact with the roller of the powder uniformization device 640, orin the vicinity of the point of contact with the roller of the powderuniformization device 640, may be reduced, significantly reduced, oreliminated.

Generally, powder deposition by a powder feeder occurs in only onedirection. For example, when printing a structure over a stationarybuild platform, a powder feeder may travel from right to left depositinga first layer of powder. In this example, the powder feeder then travelsback from left to right without depositing powder to an originallocation of the powder feeder. The powder feeder then travels from rightto left depositing a second layer of powder. Such a printing system isrelatively inefficient since an amount of time for the powder feeder totravel back from left to right is wasted.

As shown in FIG. 6 , the print system 600 addresses the issue ofwasteful movement by providing powder feeders 650, 655, which aremovable along various directions 660, 665. In this way, the powderfeeders 650, 655 allow for the deposition of a powder onto the substrate670 along each of these directions 660, 665, thereby eliminating thewasteful steps of powder feeders traveling without depositing powder.For example, the print system 600 includes two powder feeders 650, 655,which are configured to distribute or apply powder one layer at a timeover a substrate 670 in various directions. Accordingly, the powderfeeders 650, 655 improve printing efficiency of the print system 600 bybeing able to deposit powder in various directions without any wastefulmovement.

In some embodiments, the powder feeders 650, 655 may be discretedevices, disposed next to each other and configured to move together asa unit. As an example, the powder feeders 650, 655 may be integratedinto a single device allowing them to move in a synchronized fashion asa pair. Alternatively, the powder feeders 650, 655 may be integrated assingle devices allowing them to move independently from one another. Asa specific example, powder feeder 650 is activated to distribute powderand performs a pass from right to left over substrate 670, while powderfeeder 655 is prevented from distributing powder. Similarly, as powderfeeder 655 performs a pass from left to right over the substrate 670, itis activated to distribute powder, and powder feeder 650 is preventedfrom distributing powder. In further examples, powder feeders 650, 655may be stationary, and the substrate 670 may move beneath them. In thisexample, the direction of travel of the substrate 670 determines whichpowder feeder of powder feeders 650, 655 is activated to distributepowder and which is prevented from doing so. In this way, activation ofthe powder feeders 650, 655 are synchronized with a direction of travelof the powder feeders 650, 655 and/or the substrate 670 over which theytravel.

In some embodiments, the directions 660, 665 are opposing directions,with direction 660 opposing direction 665, and vice versa. As shown inFIG. 6 , powder uniformization device 640 is rotatable in directions645, 645 a, along the substrate 670. Specifically, the roller of thepowder uniformization device 640 is a counter-rotating roller, such asdescribed with respect to rollers 240, 340, and operates to compact thepowder that has been dispensed by the powder feeders 650, 655. In thisway, the powder uniformization device 640 is able to uniformize powderdeposited by the powder feeders 650, 655, regardless of a direction ofthe directions 660, 665 the powder feeders 650, 655 move along.

As an example, in order to accommodate both powder feeders 650, 655, thepowder uniformization device 640 is configured to rotate in whicheverdirection of the directions 645, 645 a that is appropriate based onwhether powder feeder 650 or powder feeder 655 is activated anddispensing powder. As a more specific example, the powder uniformizationdevice 640 rotates in a clockwise direction 645 when powder feeder 650is activated, i.e., as it moves from right to left, in direction 660.Further, the powder uniformization device 640 rotates incounter-clockwise direction 645 a when powder feeder 655 is activated,i.e., as it moves from left to right, in direction 665. In this way, toaccommodate a plurality of materials deposited by the powder feeders650, 655, the powder uniformization device 640 needs to rotate in onedirection for a first powder from powder feeder of the powder feeders650, 655, and an opposite direction for a second powder from powderfeeder of the powder feeders 650, 655. Alternatively, the powderuniformization device 640 may comprise a plurality of powderuniformization devices; with each of the plurality of powderuniformization devices activated to rotate in a direction synchronizedwith the movement and activation of one of the powder feeders 650, 655.Such a configuration can help prevent powder cross contamination when aplurality of materials is deposited.

In some embodiments, synchronization of the roller of the powderuniformization device 640 is based on which direction a powder feeder ofthe powder feeders 650, 655 is moving relative to the substrate 670, orwhich direction the substrate 670 is moving relative to the powderfeeders 650, 655. In further embodiments, a powder uniformization devicecontroller may control a rotation direction of the roller of the powderuniformization device 640, based on data related to a direction of thedirections 660, 665 of the powder feeders 650, 655, data related toactivation of the powder feeders 650, 655, and/or direction of thesubstrate 670.

In some embodiments, each direction of the directions 660, 665 isrelative to the substrate 670 in response to the substrate 670 beingstatic. In this embodiment, the print system 600 is movable along alongitudinal axis, while the substrate 670 remains static. In this way,each powder feeder of the powder feeders 650, 655 is synchronizeddepending on which direction the powder feeders 650, 655 are movingrelative to the substrate 670. Alternatively, the substrate 670 ismovable along a longitudinal axis relative to the powder feeders 650,655, thereby dictating which powder feeder of the powder feeders 650,655 needs activation. In this way, each powder feeder of the powderfeeders 650, 655 is synchronized depending on which direction thesubstrate 670 is moving relative to the powder feeders 650, 655. As aspecific example, powder feeders 650, 655 may be stationary, and thesubstrate 670 may move beneath them. In this example, the direction oftravel of the substrate 670 determines which powder feeder of the powderfeeders 650, 655 is activated to distribute powder and which isprevented from doing so. In further embodiments, the substrate 670 ismovable with respect to the print system 600 along a longitudinal axis.Accordingly, print system 600 allows for powder from the powder feeders650, 655 to be deposited on the substrate 670, regardless of whichdirection the substrate 670 is moving.

FIG. 7 illustrates a schematic representation of a print system 700 inaccordance with various example implementations described with respectto FIGS. 1-6 . With reference to FIGS. 1-6 , print system 700 includes aplurality of powder feeders 750, 755, each having a blade-shaped end.Further, FIG. 7 illustrates each powder feeder of the powder feeders750, 755 is attached to a support or mounting apparatus 710.

The print system 700 includes powder uniformization devices 720, 760,located adjacent to at least one powder feeder of the plurality ofpowder feeders 750, 755. The powder uniformization devices 720, 760uniformize powder deposited by the powder feeders 750, 755 onto thesubstrate 670. In some embodiments, the powder uniformization devices720,760 may include a roller which corresponds to rollers 340, 440, 640and may include all of their features as described with respect to FIGS.3A, 3B, 4A, 4B and 6 . For example, powder uniformization devices 720,760 may rely on counter-rotating rollers to promote uniformity of thedeposited powder. In some implementations, the powder uniformizationdevices 720, 760 may be attached to the support or mounting apparatus710 in a manner that allows them to be moved in a directionsubstantially perpendicular to the substrate 670. For a uniformizationdevice of the uniformization devices 720, 760 which is not activated torotate, a roller gap may be increased, and for a uniformization deviceof the uniformization devices 720, 760 which is activated to rotate, theroller gap may be adjusted to define a thickness of the printed layer.

The powder feeders 750, 755 may contain different powder materials, andutilization of two powder uniformization devices 720,760 ensures thatthere is no powder cross contamination. As a specific example, thepowder uniformization device 720 rotates in a clockwise direction 725when powder feeder 750 is activated, i.e., as it moves from right toleft, in the direction 660. The powder uniformization device 760 rotatesin a counter-clockwise direction 765 when powder feeder 755 isactivated, i.e., as it moves from left to right, in direction 665. Inthis way, each of the plurality of powder uniformization devices 720,760 is configured to be activated to rotate in a direction synchronizedwith the movement and activation of one of the powder feeders 750, 755.Such a configuration can help prevent powder cross contamination when aplurality of materials is deposited.

In some embodiments, synchronization of the powder uniformizationdevices 720, 760 is based on which direction a powder feeder of thepowder feeders 750, 755 is moving relative to the substrate 670, orwhich direction the substrate 670 is moving relative to the powderfeeders 750, 755. In some embodiments, each direction of the directions660, 665 is relative to the substrate 670 in response to the substrate670 being static. In this embodiment, the print system 700 is movablealong a longitudinal axis, while the substrate 670 remains static. Inthis way, each powder feeder of the powder feeders 750, 755 issynchronized depending on which direction the powder feeders 750, 755are moving relative to the substrate 670. Alternatively, the substrate670 is movable along a longitudinal axis relative to the powder feeders750, 755, thereby dictating which powder feeder of the powder feeders750, 755 needs activation. In this way, each powder feeder of the powderfeeders 750, 755 is synchronized depending on which direction thesubstrate 670 is moving relative to the powder feeders 750, 755.

In some implementations, the print system 700 further comprisesadditional compaction devices 730, 740, that are configured to rotate inthe same direction of the spreading of the deposited powder (directions735 and 745) i.e., rotate in the opposite direction to the directions725, 765 of the counter-rotating rollers of the uniformization devices720,760. In other implementations, the print system 700 may beconfigured such that powder uniformization devices 720, 760 serve asboth uniformization devices and additional compaction devices. Forexample, when powder feeder 750 is activated, i.e., as it moves fromright to left, in direction 660, the powder uniformization device 720rotates in a clockwise direction 725 and the powder uniformizationdevice 760 is operated as an additional compaction device rotating in acounterclockwise direction 765, i.e., in the opposite direction to theclockwise direction 725. Similarly, when powder feeder 755 is activated,i.e., as it moves from left to right, in direction 665, the powderuniformization device 760 rotates in the counter-clockwise direction 765and the powder uniformization device 720 is operated as an additionalcompaction device rotating in a clockwise direction 725, i.e., in theopposite direction to the counter-clockwise direction 765.

FIG. 8 illustrates a schematic representation of print system 800 inaccordance with various example implementations described with respectto FIGS. 1-7 . Print system 800 includes a plurality of powder feeders850, 850 a, 855, 855 a. The powder feeders 850, 850 a, 855, 855 a maydispense the same powder as each other, or different powders, allowingfor multi-material deposition. In some configurations, powder feeders850, 855 a may dispense a first powder material, and powder feeders 850a, 855 may dispense a second powder material. The print system 800 mayinclude one or more of the features described in relation to FIGS. 6 and7 , with the powder feeders 650, 655, 750, 755, and powderuniformization devices 640, 720, 760. For example, in embodiments, thepowder feeders 850, 850 a, 855, 855 a may correspond to powder feeders350, 450, and may include all of their features as described withrespect to FIGS. 3A, 3B, 4A, and 4B, including each powder feeder of thepowder feeders 850, 850 a, 855, 855 a having a blade-shaped end.

In some embodiments, the print system 800 may further comprise a carrierdevice, such as the carrier device 12 illustrated in FIG. 1 (which mayinclude a conveyor) to transport the substrate 670 from a first locationto a second location.

As shown in FIG. 8 , the print system 800 includes a uniformizationdevice, i.e., powder uniformization device 840, located adjacent topowder feeders 850, 850 a, 855, 855 a, for example between the pluralityof powder feeders 850, 850 a, 855, 855 a. The powder uniformizationdevice 840 uniformizes powder deposited by the powder feeders 850, 850a, 855, 855 a onto the substrate 670, and rotates in clockwise direction845 and/or counter-clockwise direction 845 a. In some embodiments, thepowder uniformization device 840 may include a roller which correspondsto rollers 340, 440, and may include all of their features as describedwith respect to FIGS. 3A, 3B, 4A, and 4B. In some embodiments, two ormore of the powder feeders 850, 850 a, 855, 855 a may contain differentpowder materials, and/or powder uniformization device 840 may comprisetwo or more powder uniformization devices (not shown). Theimplementation of two or more powder uniformization devices ensures thatthere is no powder cross contamination. For example, in a case wherepowder feeders 850, 855 a dispense a first powder material, and powderfeeders 850 a and 855 dispense a second powder material, powderuniformization device 840 may comprise two independent powderuniformization devices 840 a and 840 b (not shown). With powderuniformization 840 a operated to uniformize powder deposited by thepowder feeders 850, 855 a, and powder uniformization 840 b operated touniformize powder deposited by the powder feeders 850 a, 855.

In embodiments, the powder feeders 850, 850 a, 855, 855 a may bediscrete devices, disposed next to each other and configured to movetogether as a unit. As an example, the powder feeders 850, 850 a may beintegrated into a single device allowing them to move in a synchronizedfashion as a pair. Alternatively, the powder feeders 850, 850 a, 855,855 a may be integrated as single devices allowing them to moveindependently from one another. As a specific example, the powderfeeders 850, 850 a, 855, 855 a are synchronized with a direction oftravel of the powder feeders 850, 850 a, 855, 855 a and/or the substrate670 over which they travel. In further examples, powder feeders 850, 850a, 855 and 855 a may be stationary, and the substrate 670 may movebeneath them. In this example, the direction of travel of the substrate670 determines which powder feeder of powder feeders 850, 850 a, 855 and855 a is activated to distribute powder, and which powder feeder isprevented from doing so.

To accommodate a plurality of materials deposited by the powder feeders850, 850 a, 855, 855 a, in one embodiment the powder uniformizationdevice 840 is configured to rotate in one direction when powder isdistributed from two of the powder feeders from the powder feeders 850,850 a, 855, 855 a, (for example powder feeders 850, 855 a), and anopposite direction when powder is distributed from the other two powderfeeders 850, 850 a, 855, 855 a, (for example powder feeders 850 a, 855).Alternatively, the powder uniformization device 840 may comprise aplurality of powder uniformization devices, each of the plurality ofpowder uniformization devices activated to rotate in a directionsynchronized with the movement and activation of one or more of thepowder feeders 850, 850 a, 855, 855 a. Such a configuration can helpprevent powder cross contamination when a plurality of materials isdeposited. In yet another embodiment, the powder uniformization devicesmay be attached to the support or mounting apparatus 810 in a mannerthat allows them to be moved in a direction substantially perpendicularto the substrate 670. In a further embodiment, the powder uniformizationdevices may be attached to the support or mounting apparatus 810 in amanner that allows them to be moved in a direction at an angle less than90 degree to the substrate 670. For those uniformization devices whichare not activated to rotate, the roller gap may be increased, and forthose uniformization devices which are activated to rotate, the rollergap may be adjusted to define the final thickness of the printed layer.

The print system 800 includes a plurality of binder jetting devices 880,880 a. In one embodiment, the binder jetting devices 880, 880 a areintegrated with the powder feeders 850, 850 a, 855, 855 a to provide aunit that can move as a single device arrangement in a single pass. Forexample, the binder jetting device 880 may be integrated with powderfeeders 850, 850 a to provide a unit that can move as a single devicearrangement in a single pass. In a further embodiment, the print system800 allows for powder to be deposited by powder feeders 850, 850 a, 855,855 a, along with an injection of a binder, e.g., a UV-curable resin, bythe binder jetting devices 880, 880 a. In further embodiments, the printsystem 800 allows for the application of a fixing device, e.g., a UVradiation device, to cure the UV-curable resin. As a result, the speedof the layer formation and binder curing is substantially increasedbecause there is no need for an additional post-deposition curingprocess. In some embodiments, the powder feeders 850, 850 a, 855, 855 aand/or the powder uniformization device 840 are synchronized with thebinder jetting devices 880, 880 a. Similarly, any other devices, such asa fixing device, are similarly synchronized to be activated based on thedirection of the powder feeders 850, 850 a, 855, 855 a, which areactivated, and their location with respect to the substrate 670.

FIG. 9 illustrates a method of operation of a print system in a 3Dprinting apparatus, in accordance with various example implementations.In the process 900 of FIG. 9 , at S910, a print system of the printsystems 600, 700, 800 is arranged over a substrate 670, as shown inFIGS. 6-8 . At S920, a first powder is distributed on the substrate 670in a first direction, e.g., direction 660, using a first powder feederof the powder feeders 650, 655 of the print system 600, the powderfeeders 750, 755 of the print system 700, or powder feeders 850, 850 a,855, 855 a of the print system 800. At S930, a uniformization device,i.e., powder uniformization device 640, 720, 760, 840, located at afirst distance from the first powder feeder, uniformizes the firstpowder. At S940, a second powder is distributed on the substrate 670 ina second direction, e.g., direction 665 opposing the first direction660, using a second powder feeder of the powder feeders 650, 655 of theprinting system 600, powder feeders 750, 755 of the print system 700, orpowder feeders 850, 850 a, 855, 855 a of the print system 800. At S950,the uniformization device, e.g., powder uniformization device 640, 720,760, 840 located at a second distance from the second powder feeder,uniformizes the second powder. In some embodiments the first powderdispensed may be the same or a different material from the second powderdispensed.

In the following, further features, characteristics, and advantages ofthe instant application will be described via the following items:

Item 1: A three-dimensional (“3D”) printing system for printing on asubstrate, the printing system comprising: a plurality of powderfeeders, the plurality of powder feeders dispensing a powder on thesubstrate in a first direction and in a second direction; and a powderuniformization device located adjacent to the plurality of powderfeeders, the powder uniformization device rotatable along the substratein directions opposing the first direction and the second direction.

Item 2: The printing system of item 1, wherein the first directionopposes the second direction.

Item 3: The printing system of items 1 and 2, wherein movement of thepowder uniformization device is synchronized with movement of theplurality of powder feeders.

Item 4: The printing system of items 1-3, wherein each powder feederincludes a blade-shaped end.

Item 5: The printing system of any one of items 1-4, wherein the powderuniformization device includes a roller.

Item 6: The printing system of any one of items 1-5, wherein: thesubstrate is movable with respect to the printing system along alongitudinal axis; and the printing system is static with respect to thelongitudinal axis.

Item 7: The printing system of any one of items 1-6, wherein thesubstrate is static with respect to the printing system.

Item 8: The printing system of any one of items 1-7, wherein each powderfeeder includes a blade-shaped end, each blade-shaped end having a lowersurface substantially parallel to the substrate.

Item 9: The printing system of any one of items 1-8, wherein a distancebetween a lowest contact point of the powder uniformization device tothe substrate and a blade-shaped end of each powder feeder is equal toabout one radius of a roller of the powder uniformization device.

Item 10: The printing system of any one of items 1-9, wherein eachpowder feeder is located along a longitudinal axis of the printingsystem.

Item 11: The printing system of any one of items 1-10, wherein eachpowder feeder is located along a longitudinal axis of the substrate.

Item 12: The printing system of any one of items 1-11, wherein thepowder feeders are synchronized to move together as a unit depending onwhich direction the powder feeders are moving relative to the substrate.

Item 13: The printing system of any one of items 1-12, wherein thepowder feeders are synchronized to move together as a unit depending onwhich direction the substrate is moving relative to the powder feeders.

Item 14: The printing system of any one of items 1-13, furthercomprising a vibrating device configured to vibrate the substrate at aspecific frequency.

Item 15: The printing system of any one of items 1-14, furthercomprising a vibrating device configured to vibrate the substrate at aspecific frequency.

Item 16: The printing system of any one of items 1-15, wherein thepowder uniformization device rotates in one direction for a first powderfeeder and in an opposite direction for a second powder feeder.

Item 17: The printing system of any one of items 1-16, wherein eachpowder feeder comprises at least one of a dehumidifier, a heatingelement, and an inert gas enclosed therein.

Item 18: The printing system of any one of items 1-17, furthercomprising a cleaning device configured to remove residual powder fromthe powder uniformization device.

Item 19: The printing system of any one of items 1-18, furthercomprising a cleaning device configured to apply an electric charge tothe powder uniformization device.

Item 20: The printing system of any one of items 1-19, wherein theprinting system further includes at least one of a fixing device and abinder printer.

Item 21: The printing system of any one of items 1-20, whereinactivation of the powder feeders is synchronized with a direction oftravel of one or more of the powder feeders and the substrate.

Item 22: The printing system of any one of items 1-21, wherein theplurality of powder feeders is configured to dispense more than onepowder materials.

Item 23: A method for three-dimensional (“3D”) printing using a printingsystem, the method comprising: arranging the printing system over asubstrate; distributing a first powder on the substrate in a firstdirection using a first powder feeder of the printing system;uniformizing the first powder by a uniformization device located at afirst distance from the first powder feeder; distributing a secondpowder on the substrate in a second direction using a second powderfeeder of the printing system; and uniformizing the second powder by theuniformization device located at a second distance from the secondpowder feeder.

Item 24: The method of item 23, wherein the uniformization devicerotates in a direction opposing the first direction to uniformize thefirst powder and in another direction opposing the second direction touniformize the second powder.

Item 25: The method of any one of items 23 and 24, further comprisingsynchronizing a direction of the uniformization device based on adirection the substrate is moving relative to the first and secondpowder feeders.

Item 26: The method of any one of items 23-25, further comprisingsynchronizing a direction of the uniformization device based ondirections of the first and second powder feeders are moving relative tothe substrate.

Item 27: The method of any one of items 23-26, wherein when the firstpowder feeder is activated to dispense the first powder in the firstdirection, the second powder feeder is prevented from dispensing thesecond powder in the second direction.

While various implementations have been described, the description isintended to be exemplary, rather than limiting, and it is understoodthat many more implementations and implementations are possible that arewithin the scope of the implementations. Although many possiblecombinations of features are shown in the accompanying figures anddiscussed in this detailed description, many other combinations of thedisclosed features are possible. Any feature of any implementation maybe used in combination with or substituted for any other feature orelement in any other implementation unless specifically restricted.Therefore, it will be understood that any of the features shown and/ordiscussed in the present disclosure may be implemented together in anysuitable combination. Accordingly, the implementations are not to berestricted except in light of the attached claims and their equivalents.Also, various modifications and changes may be made within the scope ofthe attached claims.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that the teachings may beapplied in numerous applications, only some of which have been describedherein. It is intended by the following claims to claim any and allapplications, modifications and variations that fall within the truescope of the present teachings.

Unless otherwise stated, all measurements, values, ratings, positions,magnitudes, sizes, and other specifications that are set forth in thisspecification, including in the claims that follow, are approximate, notexact. They are intended to have a reasonable range that is consistentwith the functions to which they relate and with what is customary inthe art to which they pertain.

The scope of protection is limited solely by the claims that now follow.That scope is intended and should be interpreted to be as broad as isconsistent with the ordinary meaning of the language that is used in theclaims when interpreted in light of this specification and theprosecution history that follows and to encompass all structural andfunctional equivalents. Notwithstanding, none of the claims are intendedto embrace subject matter that fails to satisfy the requirement ofSections 101, 102, or 103 of the Patent Act, nor should they beinterpreted in such a way. Any unintended embracement of such subjectmatter is hereby disclaimed.

Except as stated immediately above, nothing that has been stated orillustrated is intended or should be interpreted to cause a dedicationof any component, step, feature, object, benefit, advantage, orequivalent to the public, regardless of whether it is or is not recitedin the claims.

It will be understood that the terms and expressions used herein havethe ordinary meaning as is accorded to such terms and expressions withrespect to their corresponding respective areas of inquiry and studyexcept where specific meanings have otherwise been set forth herein.

Relational terms such as first and second and the like may be usedsolely to distinguish one entity or action from another withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions. The terms “comprises,” “comprising,”or any other variation thereof, are intended to cover a non-exclusiveinclusion, such that a process, method, article, or apparatus thatcomprises a list of elements does not include only those elements butmay include other elements not expressly listed or inherent to suchprocess, method, article, or apparatus. An element proceeded by “a” or“an” does not, without further constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises the element.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various examples for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claims require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed example. Thus, the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separately claimed subject matter.

What is claimed is:
 1. A three-dimensional (“3D”) printing system forprinting on a substrate, the printing system comprising: a plurality ofpowder feeders, the plurality of powder feeders dispensing a powder onthe substrate in a first direction and in a second direction; and apowder uniformization device located adjacent to the plurality of powderfeeders, the powder uniformization device rotatable along the substratein directions opposing the first direction and the second direction. 2.The printing system of claim 1, wherein the first direction opposes thesecond direction.
 3. The printing system of claim 1, wherein movement ofthe powder uniformization device is synchronized with movement of theplurality of powder feeders.
 4. The printing system of claim 1, whereineach powder feeder includes a blade-shaped end.
 5. The printing systemof claim 1, wherein the powder uniformization device includes a roller.6. The printing system of claim 1, wherein: the substrate is movablewith respect to the printing system along a longitudinal axis; and theprinting system is static with respect to the longitudinal axis.
 7. Theprinting system of claim 1, wherein the substrate is static with respectto the printing system.
 8. The printing system of claim 1, wherein eachpowder feeder includes a blade-shaped end, each blade-shaped end havinga lower surface substantially parallel to the substrate.
 9. The printingsystem of claim 1, wherein a distance between a lowest contact point ofthe powder uniformization device to the substrate and a blade-shaped endof each powder feeder is equal to about one radius of a roller of thepowder uniformization device.
 10. The printing system of claim 1,wherein each powder feeder is located along a longitudinal axis of theprinting system.
 11. The printing system of claim 1, wherein each powderfeeder is located along a longitudinal axis of the substrate.
 12. Theprinting system of claim 1, wherein the powder feeders are synchronizedto move together as a unit depending on which direction the powderfeeders are moving relative to the substrate.
 13. The printing system ofclaim 1, wherein the powder feeders are synchronized to move together asa unit depending on which direction the substrate is moving relative tothe powder feeders.
 14. The printing system of claim 1, furthercomprising a vibrating device configured to vibrate the powderuniformization device at a specific frequency.
 15. The printing systemof claim 1, further comprising a vibrating device configured to vibratethe substrate at a specific frequency.
 16. The printing system of claim1, wherein the powder uniformization device rotates in one direction fora first powder feeder and in an opposite direction for a second powderfeeder.
 17. The printing system of claim 1, wherein each powder feedercomprises at least one of a dehumidifier, a heating element, and aninert gas enclosed therein.
 18. The printing system of claim 1, furthercomprising a cleaning device configured to remove residual powder fromthe powder uniformization device.
 19. The printing system of claim 1,further comprising a cleaning device configured to apply an electriccharge to the powder uniformization device.
 20. The printing system ofclaim 1, wherein the printing system further includes at least one of afixing device and a binder printer.
 21. The printing system of claim 1,wherein activation of the powder feeders is synchronized with adirection of travel of one or more of the powder feeders and thesubstrate.
 22. The printing system of claim 1, wherein the plurality ofpowder feeders is configured to dispense more than one powder materials.23. A method for three-dimensional (“3D”) printing using a printingsystem, the method comprising: arranging the printing system over asubstrate; distributing a first powder on the substrate in a firstdirection using a first powder feeder of the printing system;uniformizing the first powder by a uniformization device located at afirst distance from the first powder feeder; distributing a secondpowder on the substrate in a second direction using a second powderfeeder of the printing system; and uniformizing the second powder by theuniformization device located at a second distance from the secondpowder feeder.
 24. The method of claim 23, wherein the uniformizationdevice rotates in a direction opposing the first direction to uniformizethe first powder and in another direction opposing the second directionto uniformize the second powder.
 25. The method of claim 23, furthercomprising synchronizing a direction of the uniformization device basedon a direction the substrate is moving relative to the first and secondpowder feeders.
 26. The method of claim 23, further comprisingsynchronizing a direction of the uniformization device based ondirections of the first and second powder feeders are moving relative tothe substrate.
 27. The method of claim 23, wherein when the first powderfeeder is activated to dispense the first powder in the first direction,the second powder feeder is prevented from dispensing the second powderin the second direction.